During the few decades, the restaurant and, particularly, the fast food types of outlets, have proliferated to an almost unbelievable extent, not only in the United States, but in many foreign countries.
It has always been a problem with cooking over a stove, even in homes, that with the heating of food, vapors of various types arise from the cooking utensils or from griddles or grills, which vapors or fumes are usually entrained with grease or other particulates given off by the food or by whatever is used to cook the food, e.g., grease, butter, olive oil, etc. Even in a home kitchen, after a while it will be noticed that any area above the stove becomes greasy, discolored, or both. This condition is caused by smoke, fumes or any other gaseous medium which emanates from he cooking process.
In recent years, the kitchens of many homes have been provided with some type of a hood disposed above the stove, such hood having an upper outlet, either in communication with the outside atmosphere through the house roof or, with an adjacent chimney leading up to the atmosphere. Over a period of time, the insides of these hoods will become greasy unless the rising smoke, fumes, or gaseous medium is required to be passed through some type of filter. In the case of restaurants and fast food establishments, filtering is quite necessary and, in some instances, mandated by local municipal or state codes.
The filters themselves tend to pick up and extract from the rising gaseous medium much of the entrained grease or other particulates with the result that, after a certain period of time, the filters become fouled and must be cleaned or replaced. In homes, this may become necessary only periodically, such as once every month or two. However, in the case of restaurants where cooking is engaged in during most of the restaurant's or fast food establishment's open hours, filters may become clogged, or, at least, desirable to clean them as frequently as once a day.
The desirability of cleaning filters by washing and without removing the filters from a hood or other structure above the cooking area has long been recognized as many expedients have been devised to effect such washing. Examples of such expedients may be found in the following U.S. Pat. Nos. 3,785,124, 3,805,685 3,854,388, 4,071,019, 4,101,299, and 4,231,769. The apparatus of some of these patents may be found to be effective, but their cost in installing them may be too great, particularly where a system is desired for a residential use.
What is needed therefore is a relatively simple system which can be installed in residences at a reasonable price and can also be adapted in larger sizes for use in restaurants or other commercial food establishments.